Cannon, who was born in Prairie du Chien, Wisconsin, graduated from Harvard in 1896 and was professor of physiology there from 1906 to 1942. His early work included studies of the digestive system, in particular the use of x-rays to study stomach disorders. For this he introduced the bismuth meal. Most of his working life, however, was spent studying the nervous system, particularly the way in which various body functions are regulated by hormones. As early as 1915 he showed the connection between secretions of the endocrine glands and the emotions. In the 1930s he worked on the role of epinephrine in helping the body to meet ‘fight or flight’ situations. He also studied the way hormonelike substances are involved in transmitting messages along nerves.